Effects of plant growth-promoting rhizobacteria on organic tomato seedling production

The aim of this research was to determine the effects of different plant growth promoting rhizobacteria (PGPR) on organic tomato seedling growth in peat and vermicompost mixture used as growing medium. Organic tomato seeds (Lycopersicon esculentum 'Melis') were treated with bacterial strains named as Pseudomonas punonensis strains 37 and 56, Pseudomonas putida strain 18/1K, Ochrobactrum pseudintermedium strain 80, Pantoea agglomerans strain 83, Bacillus subtilis strain 66/3, Bacillus thuringiensis strain 99, Pseudomonas fluorescens strains 112, S5/4, 30, and TR21/1. Treated and control seeds were sown into local peat+vermicompost (LP+VC) (1.5: 1, v: v) on July 24, 2014. Trays were left in germination room for 3 days at 24/24 degrees C (day/night) and 80% relative humidity. After germination, plants were moved to a PE greenhouse which is specialized for seedling growing. Seedlings were fertilized by liquid composted farmyard manure (30 L ha(-1)) and they were ready for transplanting after a month. Seed germination period and rate, fresh and dry weights and nutrient composition of shoots and roots were determined. Pantoea agglomerans and Pseudomonas punonensis were found as promising on shoot and root growth respectively in organic tomato seedling production.